Regarding UBI scalability

Adrian Hunter ext-adrian.hunter at
Mon Feb 2 06:18:15 EST 2009

Artem Bityutskiy wrote:
> On Mon, 2009-02-02 at 13:07 +0200, Adrian Hunter wrote:
>> I would suggest an intermediate step.  Create UBI2 which is
>> similar to UBI but stores eraseblock information in one place,
>> instead of at the beginning of each eraseblock.  Such an approach
>> might be OK up to as much as 64GiB, and would probably perform
>> better than a fully scalable version.
>> Then look at creating UBI3, which is fully scalable.
> Yes, I assume UBI2 should store mapping/erasure information in separate
> tables, not in each eraseblock. So we should get rid of eraseblock
> headers.

Yes that is what I meant.  You could probably make do with as little as
12 bytes per eraseblock so a 64GiB flash with 512KiB eraseblock size
would need 1536KiB table, which could be read in a second or two, so
mount time is OK.

I have an idea for how to update the table relatively efficiently if you
are interested.

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